Limits for generalized sidelobe cancellers with embedded acoustic echo cancellation

This paper analyzes positive synergies and theoretical limits of the combination of acoustic echo cancellation (AEC) and Generalized Sidelobe Cancellers (GSC) for the removal of echoes of loudspeaker signals and local interferers. While the proposed system only requires one AEC for an arbitrary number of microphones, the array gain is limited by the number of sensor channels when all interferers arrive from different directions-of-arrival (DOAs). The paper also shows that the degrees of freedom of the adaptive sidelobe cancelling path are not sufficient when local interferers and acoustic echoes have common DOAs.